-    CALCITE     -    CaCO3

Theoretical atomic positions and lattice parameters at experimental volum from AMCSD; Isotope composition: C-14 

Crystal Structure 


Because of the translational symmetry all the calculations are performed in the primitive unit cell and not in the conventional unit cell. The following information regarding the structure is given with respect to this primitive unit cell, which sometimes can take an unintuitive shape.

Symmetry (experimental): 

Space group:  167  R-3c 
Lattice parameters (Å):  2.5930  2.5930  8.9431 
Angles (°):  90.0  90.0  120.0 

Symmetry (theoretical): 

Space group:  167  R-3c 
Lattice parameters (Å):  6.3310  6.3310  6.3310 
Angles (°):  46.7  46.7  46.7 

Cell contents: 

Number of atoms:  10 
Number of atom types: 
Chemical composition: 

Atomic positions (theoretical):

Ca:  0.0000  0.0000  0.0000 
C:  0.2500  0.2500  0.2500 
O:  0.5050  0.9950  0.2500 
O:  0.9950  0.2500  0.5050 
Ca:  0.5000  0.5000  0.5000 
C:  0.7500  0.7500  0.7500 
O:  0.7500  0.4950  0.0050 
O:  0.2500  0.5050  0.9950 
O:  0.4950  0.0050  0.7500 
O:  0.0050  0.7500  0.4950 
Atom type 

We have listed here the reduced coordinates of all the atoms in the primitive unit cell.
It is enough to know only the position of the atoms from the assymetrical unit cell and then use the symmetry to build the whole crystal structure.

Visualization of the crystal structure: 

Size:

  
Nx:  Ny:  Nz:    
You can define the size of the supercell to be displayed in the jmol panel as integer translations along the three crys­tallo­gra­phic axis.
Please note that the structure is represented using the pri­mi­tive cell, and not the conventional one.
     

Powder Raman 

Powder Raman spectrum

The intensity of the Raman peaks is computed within the density-functional perturbation theory. The intensity depends on the temperature (for now fixed at 300K), frequency of the input laser (for now fixed at 21834 cm-1, frequency of the phonon mode and the Raman tensor. The Raman tensor represents the derivative of the dielectric tensor during the atomic displacement that corresponds to the phonon vibration. The Raman tensor is related to the polarizability of a specific phonon mode.

Horizontal:
Xmin:
Xmax:
Vertical:
Ymin:
Ymax:
 
Choose the polarization of the lasers.
I ∥ 
I ⊥ 
I Total 

Data about the phonon modes

Frequency of the transverse (TO) and longitudinal (LO) phonon modes in the zone-center. The longitudinal modes are computed along the three cartesian directions. You can visualize the atomic displacement pattern corresponding to each phonon by clicking on the appropriate cell in the table below.

1
ac
0
0
0
0
2
ac
0
0
0
0
3
ac
0
0
0
0
4
A2u
93
93
93
108
5
Eu
108
108
108
108
6
Eu
108
128
128
141
7
Eg
157
157
157
157
4.928e+39
7.6
7.119e+39
10.9
1.205e+40
18.5
8
Eg
157
157
157
157
4.928e+39
7.6
7.059e+39
10.8
1.199e+40
18.4
9
A2g
160
160
160
160
10
Eu
244
244
244
244
11
Eu
244
260
260
244
12
Eg
296
296
296
296
1.260e+40
19.3
1.195e+40
18.3
2.455e+40
37.6
13
Eg
296
296
296
296
1.260e+40
19.3
1.962e+40
30.1
3.222e+40
49.4
14
A1u
299
299
299
299
15
A2g
324
324
324
324
16
Eu
331
331
331
331
17
Eu
331
347
347
331
18
A2u
347
400
400
422
19
Eg
700
700
700
700
1.994e+39
3.1
2.224e+39
3.4
4.218e+39
6.5
20
Eg
700
700
700
700
1.994e+39
3.1
1.783e+39
2.7
3.776e+39
5.8
21
Eu
703
703
703
703
22
Eu
703
706
706
703
23
A2u
800
800
800
807
24
A2g
807
807
807
818
25
A1g
1092
1092
1092
1092
1.108e+39
1.7
3.509e+37
0.1
1.143e+39
1.8
26
A1u
1092
1092
1092
1092
6.321e+40
96.9
2.002e+39
3.1
6.521e+40
100.0
27
Eu
1339
1339
1339
1339
28
Eu
1339
1363
1363
1339
29
Eg
1363
1363
1363
1363
2.095e+39
3.2
2.327e+39
3.6
4.422e+39
6.8
30
Eg
1363
1476
1476
1363
2.095e+39
3.2
1.854e+39
2.8
3.949e+39
6.1
No.  Char.  ω TO  ω LOx  ω LOy  ω LOz  I ∥  I ⊥  I Total 
You can define the size of the supercell for the visualization of the vibration.
Nx: 
Ny: 
Nz: 
Normalized
Raw
Options for intensity.